Congress will seek the answer to that question and others this week as it presses General Motors CEO Mary Barra and federal regulators about their handling of a safety defect in the Chevrolet Cobalt and other small cars.

The hearings -- before a House subcommittee Tuesday and a Senate subcommittee Wednesday -- will likely be tense and emotional. At least a dozen family members of victims will attend, wearing blue shirts featuring a photo of 16-year-old Amber Marie Rose, who was killed in a 2005 Cobalt crash, and the words "Protect Our Children." Barra will surely apologize, as she has before, for the loss of life.

The company on Monday said it was recalling 1.3 million vehicles in the U.S. because the electronic power-steering assist can suddenly stop working. Included in the recall are the Chevrolet Malibu, Malibu Maxx, Chevrolet HHR, Saturn Aura, Saturn Ion and Pontiac G6. All of the vehicles are from the 2010 model year or earlier. The new recall brings to 6.1 million the number of vehicles GM has recalled since February.

Barra may try to limit her answers to Congress, citing an ongoing internal review and government investigations. For his part, David Friedman, the acting head of the National Highway Traffic Safety Administration, may try to shift blame from his agency to GM, saying the company withheld information. Either approach could annoy committee members, who will want to know why the system failed and ensure consumers that they're adequately protected no matter what car they drive.

In particular, Congress wants to know if it needs to strengthen a 2000 law intended to improve communication between automakers and the government. Here are some questions lawmakers are likely to ask Barra and Friedman, and why:

GM Q: Why did it take so long to recall these vehicles?

Background: GM's own timeline, provided to the government, indicates that it knew as early as 2001 that there were problems with the ignition switch in the Saturn Ion. That switch was later used in the Cobalt and other cars. GM eventually learned of accidents and fatalities linked to the switch, and conducted multiple reviews. Yet the cars were only recalled this year. Barra will need to explain why GM didn't act sooner.

Q: Why was a proposed fix never implemented?

Background: According to a timeline prepared by the House subcommittee, GM engineers developed a fix for the switch in 2004, but it was canceled in 2005 because of its long lead time and cost. Engineers also devised a new key design that would prevent the key from falling out of the ignition, which caused the engine to stall. The fix was approved but later canceled. Lawmakers will want to know why, and who was involved. Barra may not be willing to name names at this point. She has said she only learned of the problem last December, shortly after being named CEO.

Q: Shouldn't GM tell owners to stop driving the recalled cars until they are fixed?

Background: GM insists that the cars are safe as long as owners remove anything extra from their key chains, to avoid weighing down the ignition switch. And dealers have permission to give loaner cars to concerned customers until GM can fix their cars. Sen. Richard Blumenthal, D-Conn., who sits on the Senate subcommittee, is among those calling for GM to make a stronger statement and tell owners to stop driving their cars immediately.

NHTSA -- Q: Why didn't NHTSA open an investigation, which is often the first step toward a recall?

Background: As early as 2005, the agency had numerous consumer complaints, service bulletins GM sent to dealers describing the ignition problems and data from a fatal crash in Maryland. And in late 2007, one official recommended investigating reports that air bags in the cars weren't deploying. An agency panel decided against that because it said a trend wasn't evident. Lawmakers want NHTSA to explain why that wasn't enough, and in general how it decides to open an investigation.

Q: Did NHTSA get enough information from GM?

Background: Safety regulators have sent GM a special order to get more information on the recall, but the automaker's response isn't due until Thursday. The head of the Department of Transportation, which oversees NHTSA, said recently that the agency lacked sufficient information about the problem from GM. But the committee's timeline shows that on two occasions -- in 2006 and 2007 -- GM honored requests for more information about two fatal crashes.

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Q: Does NHTSA have the staff and expertise to deal with the volume of data it's getting?

Background: After the Ford-Firestone tire recall in the late 1990s, Congress required automakers to report more information to the government about possible defects. NHTSA also gets more than 40,000 complaints per year from drivers. Lawmakers want to know if they agency has the resources to do its job.